My recumbent trike with batteries weighs ~16 kg, well will when its new LiPo arrives.
A 2 wheeler should be significantly lighter, as a sports style bike a couple of years ago was 9.5 kg and around $500 au plus a light weight hub say 2kg, lipo 1.1 kg so say below 14 kg would be a good weight.
Weight makes a lot of difference on an ebike in acceleration, hill climbing and range. I had a 40 kg electric scooter (low powered) a long time back and 10 kg was the difference between flying up a hill or struggling.
the other biggy is ride ability if the power fails, my trike is a pleasure to pedal still.
I like both crank and geared hub drives, the crank is better at extreme hill climbing say greater than 20%, but I have recently found that a hub IF you can add a reasonable amount of power is maybe more power efficient (same hub similar bike), so my new view is that they are both good but if you throw in off road I think a crank system would have to be better.
Oh and in answer to the OP's question, a light weight recumbent e-trike